Later Ms Ardern and MPs were welcomed at Parliament where she gave a short speech.

In the morning, Bill English, leader of the conservative National Party, resigned as Prime Minister. His party had failed to strike a coalition deal despite winning the largest number of votes at the September 23 election.

Ms Ardern (37) took the helm of the country's opposition party on July 31 and has since been compared to France's Emmanuel Macron and Canada's Justin Trudeau as part of a new breed of young, charismatic liberal leaders.

Under her leadership, the country of 4.8 million inhabitants is set to tighten immigration and curb foreign property ownership.

In her first major speech in her new role, Ms Ardern said that her government will "introduce a law to ban overseas speculators from buying existing homes, and we'll do it by Christmas."

Ms Ardern arrived to rapturous applause and a standing ovation at the Council of Trade Unions conference in Wellington yesterday. She outlined a series of worker-friendly policies that will undo the work of the National Government, which had been in power for nine years.

The incoming Government will also lift the minimum wage to $20 an hour by April 2021, scrap the 90-day workers' trial, and introduce Fair Pay Agreements to set industry standards for pay and conditions.

Ms Ardern said the unemployment rate should be below 4%. It is currently 4.8% - the lowest since 2008.

She also offered an olive branch to businesses, saying she would ask a tax working group to look at ways to help small businesses, such as a lower company tax rate for businesses with small turnover.

Earlier yesterday, Ms Ardern announced her Cabinet and executive. In addition to holding Arts, Culture and Heritage and National Security and Intelligence, she will also have a new portfolio for Child Poverty Reduction.

"It's a personal priority for me, a commitment for me, one of the reasons I am in politics. It's my intention that I will establish a unit within [the Department of the Prime Minister and Cabinet] to undertake that work across government departments."